Energy-autonomous optical wireless communication system

Abstract

An optical wireless communication receiver includes one or more harvesting solar cells configured to transform light into electrical power; one or more communication solar cells configured to transform light into an electrical signal embedding information; a rechargeable battery configured to store the electrical power generated by the one or more harvesting solar cells; a communication module configured to decode the electrical signal generated by the one or more communication solar cells and extract the information; a first switch configured to connect the one or more harvesting solar cells to the rechargeable battery for a harvesting-first state, and to the communication module for a communication-second state; a second switch configured to connect the one or more communication solar cells to the communication module for a communication-first state, and to the rechargeable battery for a harvesting-second state; and a microprocessor configured to control the first and second switches.

What is claimed is: 
     
       1. An optical wireless communication receiver comprising:
 one or more harvesting solar cells configured to transform light into electrical power; 
 one or more communication solar cells configured to transform light into an electrical signal embedding information; 
 a rechargeable battery configured to store the electrical power generated by the one or more harvesting solar cells; 
 a communication module configured to decode the electrical signal generated by the one or more communication solar cells and extract the information; 
 a first switch configured to connect the one or more harvesting solar cells to the rechargeable battery for a harvesting-first state, and to the communication module for a communication-second state; 
 a second switch configured to connect the one or more communication solar cells to the communication module for a communication-first state, and to the rechargeable battery for a harvesting-second state; and 
 a microprocessor configured to control the first and second switches based exclusively on (1) data stored in the electrical signal embedding information, or (2) a measurement of a data speed through the communication module. 
 
     
     
       2. The receiver of  claim 1 , wherein the one or more harvesting solar cells are interleaved with the one or more communication solar cells along a first axis. 
     
     
       3. The receiver of  claim 1 , wherein there is no other power source in the receiver. 
     
     
       4. The receiver of  claim 1 , wherein an area of a solar cell of the one or more harvesting solar cells is larger than an area of a solar cell of the one or more communication solar cells. 
     
     
       5. The receiver of  claim 1 , wherein the microprocessor is configured to instruct the first switch to change from the harvesting-first state to the communication-second state so that an electrical signal generated by the one or more harvesting solar cells is sent to the communication module as the harvesting solar cells act as communication solar cells. 
     
     
       6. The receiver of  claim 5 , wherein the microprocessor instructs the first switch to change from the harvesting-first state to the communication-second state when a data communication speed is above a given threshold. 
     
     
       7. The receiver of  claim 1 , wherein the microprocessor is configured to instruct the second switch to change from the communication-first state to the harvesting-second state so that the electrical signal generated by the one or more communication solar cells are added as electrical power to the rechargeable battery. 
     
     
       8. The receiver of  claim 7 , wherein the microprocessor instructs the second switch to change from the communication-first state to the harvesting-second state when a power level in the rechargeable battery is below a given threshold. 
     
     
       9. The receiver of  claim 1 , wherein the one or more harvesting solar cells are made of a different material from the one or more communication solar cells. 
     
     
       10. The receiver of  claim 1 , wherein the one or more harvesting solar cells are most sensitive to a first wavelength and the one or more communication solar cells are most sensitive to a second wavelength, which is different from the first wavelength. 
     
     
       11. A method for harvesting energy and communicating data, the method comprising:
 receiving light at one or more harvesting solar cells and transforming the light into electrical power; 
 storing the electrical power at a rechargeable battery; 
 receiving the light at one or more communication solar cells and transforming the light into an electrical signal embedded with information; and 
 decoding at a communication module the electrical signal generated by the one or more communication solar cells and extracting the information, 
 wherein the one or more harvesting solar cells, the rechargeable battery, the one or more communication solar cells, and the communication module are part of a single optical wireless communication receiver, and 
 wherein the steps of storing and decoding are taking place at a same time. 
 
     
     
       12. The method of  claim 11 , further comprising:
 changing a harvesting-first state of a first switch, which electrically connects the one or more harvesting solar cells to the rechargeable battery, to a communication-second state, so that the first switch electrically connects the one or more harvesting solar cells to the communication module as the harvesting solar cells act as communication solar cells. 
 
     
     
       13. The method of  claim 12 , further comprising:
 changing a communication-first state of a second switch, which electrically connects the one or more communication solar cells to the communication module, to a harvesting-second state, so that the second switch electrically connects the communication solar cells to the rechargeable battery. 
 
     
     
       14. The method of  claim 13 , further comprising:
 measuring with a microprocessor a speed of data and changing the first switch from the harvesting-first state to the communication-second state when the speed is above a given speed threshold. 
 
     
     
       15. The method of  claim 13 , further comprising:
 measuring a power level of the rechargeable battery and changing the second switch from the communication-first state to the harvesting-second state when the power level is below a power threshold. 
 
     
     
       16. The method of  claim 11 , wherein the one or more harvesting solar cells are interleaved with the one or more communication solar cells along two mutually perpendicular axes. 
     
     
       17. The method of  claim 11 , wherein the one or more harvesting solar cells are most sensitive to a first wavelength and the one or more communication solar cells are most sensitive to a second wavelength, which is different from the first wavelength. 
     
     
       18. An optical communication and energy harvesting system comprising:
 a transmitter configured to generate a light beam that encodes data; and 
 an optical wireless communication receiver configured to simultaneously use the light beam for generating electrical power and to extract the encoded data, 
 wherein the optical wireless communication receiver includes,
 one or more harvesting solar cells configured to transform the light beam into the electrical power, and 
 one or more communication solar cells configured to transform the light beam into an electrical signal embedded with the data. 
 
 
     
     
       19. The system of  claim 18 , wherein the optical wireless communication receiver further comprises:
 a rechargeable battery configured to store the electrical power generated by the one or more harvesting solar cells; 
 a communication module configured to decode the electrical signal generated by the one or more communication solar cells and extract the data; 
 a first switch configured to connect the one or more harvesting solar cells to the rechargeable battery for a harvesting-first state, and to the communication module for a communication-second state; 
 a second switch configured to connect the one or more communication solar cells to the communication module for a communication-first state, and to the rechargeable battery for a harvesting-second state; and 
 a microprocessor configured to control the first and second switches. 
 
     
     
       20. The system of  claim 19 , wherein the one or more harvesting solar cells are interleaved with the one or more communication solar cells along two mutually perpendicular axes.